# Xanadu and HyperLight cut optical switch loss to 7 mdB on a thin-film lithium niobate chip

- Published: 2026-11-11 05:29 UTC
- Section: Digital & Computing › Quantum technology
- Tags: Xanadu, HyperLight, optical switch loss, 7 mdB, thin-film lithium niobate, TFLN Chiplet, photonic quantum computer, insertion loss, wafer manufacturing
- URL: https://realtech.media/news/rt-f7f62e5c4267d15dd6f50be9_xanadu_and_hyperlight/

**The companies report a component-level measurement of 7 mdB, about a third of the roughly 20 mdB published in 2025. In photonic quantum computers, photon loss accumulates across switches.**

![Xanadu and HyperLight cut optical switch loss to 7 mdB on a thin-film lithium niobate chip](https://realtech.media/media/2026/11/3f07e164690f44d0.jpg)
*JonathanMarks, Wikimedia Commons, CC BY-SA 4.0*

Xanadu and HyperLight announced on November 10, 2026 that the insertion loss of an optical switch for photonic quantum computing has been reduced to 7 mdB (0.007 dB), according to xenospectrum.com [1]. The switch routes the photons that carry quantum information. In 2025 the companies reported about 20 mdB, so the figure fell by roughly a third [1]. A loss of 7 mdB corresponds to a transmittance of about 99.84%, meaning about 0.16% of the light is lost per pass [1].

The switches are built from thin-film lithium niobate (TFLN) on HyperLight's TFLN Chiplet platform. The companies state that the result was demonstrated on a wafer production line suited to volume manufacturing, and that it is a measurement of fabricated parts, not a simulation [1]. The July 29, 2025 announcement also cited a volume-capable facility, so the new element is a lower loss on a similar manufacturing base [1].

## Why photon loss matters

Unlike ordinary optical communication, a photon carrying quantum information cannot simply be restored with an optical amplifier without risking damage to the quantum state [1]. Losses in successive switches add up. In an editorial calculation by XenoSpectrum, 100 passes through identical switches with no other losses leave about 63.1% of the light at 20 mdB and about 85.1% at 7 mdB [1]. This is a simple conversion of published values, not an experiment or a simulation of a quantum computer, and it does not imply that a real device uses 100 stages [1].

## What remains unreported

The companies say yield and reproducibility are high, but no yield figures or loss distribution across devices were published [1]. It is not stated whether 7 mdB is a mean, typical or best value, nor how many devices were measured, the measurement error, the wavelength, the temperature or the drive conditions [1]. It is also unclear whether the 2025 and 2026 measurements used the same conditions [1]. No academic paper accompanies the figure, which comes from a press release, and no independent replication is cited [1].

Xanadu CEO Christian Weedbrook expects better manufacturing economics and a smaller footprint, but this is an outlook, not a result demonstrated in the experiment [1]. The effect on whole-system cost, size and error rate has not been shown [1].

## Sources

1. [xenospectrum.com](https://xenospectrum.com/xanadu-hyperlight-optical-switch-loss)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-f7f62e5c4267d15dd6f50be9_xanadu_and_hyperlight/